WASHINGTON (Reuters) - One of the most unpopular and unproductive U.S. Congresses in modern history returns on Monday from a five-week recess, facing a crush of big tasks, few of which will likely get done.

Lawmakers are expected to be in Washington for only about two weeks between now and the November 6 election, making their return to the capital little more than a pit stop.

"Everyone wants to get out of town -- fast," said a top Senate aide, voicing the sentiment on both sides of the political aisle.

Quickie sessions are the rule rather than the exception in election years, and lawmakers may be around just long enough to approve a must-pass spending bill to keep the government running before racing home to campaign for their seats.

This year they do will so as voters seem more frustrated than ever with their partisan gridlock.

Unfinished business on Capitol Hill includes bills to overhaul the massive farm law, improve cyber security for the nation's critical infrastructure, downsize the ailing postal service, and normalize trade with Russia.

The most urgent item -- making sure Congress does not trigger a recession early next year -- is by all accounts on hold until after the election, when lawmakers will attempt to head off trouble of their own making: tax increases and automatic spending cuts that threaten to send the United States over what's been called "a fiscal cliff."

Corporate leaders say the uncertainty surrounding this single issue is already weighing on business decisions, particularly in the defence industry.

A preventable recession, induced by a forewarned Congress, would be a first. Most still believe lawmakers will avoid going over the cliff, some how, some way.

"My faith in Congress is pretty minimal," said Dan Ripp of Bradley Woods, a New York-based public policy research firm.

"But members of Congress are excellent at self-preservation and that is why I think they will do something to avoid 'the cliff' and voter backlash," Ripp said.

Nevertheless, any progress may depend on how party leaders analyze the results of the election contest between President Barack Obama and Republican challenger Mitt Romney.

Lawmakers will calculate whether they have something to gain -- or lose -- by waiting until the convening of a new Congress in January to deal with tax and spending issues.

LEGISLATIVE GRIDLOCK

Thus a pre-election paralysis has taken hold on top of the gridlock that has afflicted Washington since the 2010 election, when Democrats lost control of the House of Representatives and government became officially divided along party lines.

Just 61 bills have become law in 2012, the fewest in a year in more than 60 years, according to records compiled by the House clerk's office.

In 2011, 90 bills became law, down from 258 the year before, when Democrats controlled both chambers and the White House.

"The metaphor for congressional ineptitude is its inability to even reform the postal service," said Greg Valliere of the Potomac Research Group, a private firm that tracks Washington for institutional investors.

"Members in both parties talk tough about reducing deficits, but they are scared to close a local post office because they will get angry letters from constituents," Valliere said.

"If you can't reform the post office, how are you ever going to reform entitlements" like the Social Security retirement program and Medicare health program, he said.

Amid budget battles last year, Congress pushed the government to the brink of a shutdown and an unprecedented default, generating plenty of public disgust, anger and fear.

During the past year or so, Congress's approval ratings have been in or at single digits, the lowest numbers ever.

Even so, most lawmakers seem certain to win another term, largely because of the advantages of incumbency, such as name recognition and the ability to raise money.

Larry Sabato of the University of Virginia's Center for Politics said voters were puzzled as to why lawmakers cannot be more productive.

"Most people just don't understand why Democrats and Republicans can't get together and split at least some of their differences," Sabato said.

Members of Congress certainly have plenty of time to clear their heads, stretch their legs and literally find common ground outside of Washington.

While the average American worker has a median household income of about $50,000 (31,222.68 pounds) and gets 13 days of annual paid vacation, lawmakers command salaries of $174,000 and will have recesses this year totalling more than four months.

Lawmakers do not thought call their recesses vacation. Instead, they refer to many of them as "district work periods" used to meet with constituents.

Democrats and Republicans spent some of their recent recess at their political parties' respective national conventions.

However, with Congress in such low esteem, lawmakers maintained low profiles at the nationally broadcast events, which featured prime-time speeches by Obama and Romney.

On a recent rainy day, out-of-town visitors to the U.S. Capitol voiced frustrations.

"I want to have faith in them, I really do, but it is hard," said Ronda Rieves, a Florida pastor, accompanied by her husband, Franklin, a construction worker.

"The only time we hear from them is every two years, on a recording that says, 'Vote for me,'" she said.

Edward Harrison, a Colorado chemist, said: "We have the government we deserve. They represent who we are -- partisan and unwilling to compromise for personal or ideological reasons."

Despite this, Harrison said he remained "pragmatically optimistic."

"Congress made it through the Civil War," he said. "They can make it through this."